Ferrule coupling to on-die optical socket

ABSTRACT

An optical ferrule includes a substrate formed of a diced wafer and a molded structure formed on the substrate. The molded structure may be formed of a curable material. The molded structure may include a plurality of grooves for positioning a plurality of optical fibers therealong, respectively, a plurality of reflective surfaces formed to reflect optical signals from ends of the plurality of optical fibers, respectively, or reflect incident optical signals towards the ends of the plurality of optical fibers, respectively, and an alignment structure disposed to be aligned to a corresponding alignment structure of a socket to which the optical ferrule is coupled.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of and claims priority toapplication Ser. No. 16/059,015, filed on Aug. 8, 2018, the contents ofwhich is hereby incorporated by reference in its entirety.

BACKGROUND

Tight-tolerance coupling of optical transmission lines between opticalconnectors, such as optical fibers in optical ferrules and opticalwaveguides in photonic integrated circuits, is important to reducecoupling loss of optical signals. Especially, single mode coupling lossis highly sensitive to misalignment of optical transmission lines inmodularly mating optical connectors. For example, position offset of asmall amount (e.g., <2 μm) and tilt offset of a small amount (e.g., <1deg) can cause significant coupling loss (e.g., >−1 dB). Suchmisalignment can be caused by mismatch of coefficients of thermalexpansion (CTE) among materials used for or around optical transmissionlines coupled via modularly mating optical connectors. When a pluralityof optical transmission lines are coupled in parallel, the misalignmentcaused by mismatch of CTE can become larger as every transmission linebecomes away from a center of a correspondingly coupled transmissionline differently than other coupled transmission lines within an opticalferrule.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain features of various embodiments of the present technology areset forth with particularity in the appended claims. A betterunderstanding of the features and advantages of the technology will beobtained by reference to the following detailed description that setsforth illustrative embodiments, in which the principles of the inventionare utilized, and the accompanying drawings of which:

FIG. 1 is a schematic diagram illustrating a plan view of an example ofa wafer on which a plurality of molded structures for optical ferrulesis formed.

FIG. 2 is a schematic diagram illustrating an example of an opticalferrule according to some embodiments.

FIG. 3 is a schematic diagram illustrating an example of the opticalferrule shown in FIG. 2 coupled to a socket according to someembodiments.

FIG. 4 is a schematic diagram illustrating an example of a process forcoupling a socket to an optical ferrule according to some embodiments.

FIG. 5 is a schematic diagram illustrating another example of an opticalferrule according to some embodiments.

FIG. 6 is a schematic diagram illustrating an example of the opticalferrule shown in FIG. 5 coupled to a socket according to someembodiments.

FIG. 7 is a schematic diagram illustrating still another example of anoptical ferrule according to some embodiments.

FIG. 8 is a schematic diagram illustrating an example of the opticalferrule shown in FIG. 7 coupled to a socket according to someembodiments.

FIG. 9 is a schematic diagram illustrating still another example of anoptical ferrule according to some embodiments.

FIG. 10 is a schematic diagram illustrating an example of the opticalferrule shown in FIG. 9 coupled to a socket according to someembodiments.

FIG. 11-14 are schematic diagrams illustrating other examples of anoptical ferrule according to some embodiments.

DETAILED DESCRIPTION

Various embodiments described herein are directed to an optical ferruleand a socket for coupling with the optical ferrule. Conventional opticalferrules and sockets are not sufficient to restrain coupling loss causedby misalignment of single-mode optical transmission lines (e.g. opticalfibers). In order to achieve optical coupling with less coupling loss,an optical ferrule of some embodiments of the present disclosure isformed by using optical ferrule structure on a wafer using wafer scalemicro-optic manufacturing. Wafer scale micro-optic manufacturing hasbeen employed for micro optical elements, such as micro lenses,diffractive filters, polarizers, and so on.

An optical ferrule according to some embodiments includes a substrateformed of a diced wafer and a molded structure formed on the substrate.The molded structure may be formed of a light curable material. Themolded structure may include a plurality of grooves for positioning aplurality of optical fibers therealong, respectively. The moldedstructure may also include a plurality of reflective surfaces formed toreflect optical signals from ends of the plurality of optical fibers,respectively, or reflect incident optical signals towards the ends ofthe plurality of optical fibers, respectively. The molded structure mayalso include an alignment structure disposed to be aligned to acorresponding alignment structure of a socket to which the opticalferrule is coupled.

In some embodiments, the plurality of reflective surfaces are formed toreflect the optical signals from ends of the plurality of optical fiberssuch that the reflected optical signals pass through the substrate. Insome embodiments, the plurality of reflective surfaces are formed toreflect the optical signals from ends of the plurality of optical fibersto a direction away from the substrate. In some embodiments, the moldedstructure further includes a gap extending along the plurality ofgrooves and separating the molded structure into a plurality ofportions. In some embodiments, the alignment structure of the moldedstructure includes one or more guide rails extending along the pluralityof grooves. In some embodiments, the alignment structure of the moldedstructure includes one or more guide pillars extending away from thesubstrate. In some embodiments, the alignment structure of the moldedstructure includes one or more recesses formed on one or more regions ofthe molded structure. In some embodiments, the substrate may have acoefficient of thermal expansion (CTE) matched to a CTE of the moldedstructure.

A socket for coupling with an optical ferrule according to someembodiments includes a base, a socket body, and an alignment structure.The base has embedded optical transmission lines and means for theoptical lights to be coupled to the ferrule via light deflectors, e.g.,grating couplers. The socket body is formed on the base, and includes aferrule slot in which the optical ferrule fits. The alignment structureis formed to be aligned to a corresponding alignment structure of theoptical ferrule in order for the light paths to be aligned between theoptical ferrule and the base. Here, an optical transmission line mayinclude optical ferrules (for ferrule to ferrule coupling), opticalwaveguides (for ferrule to waveguide coupling) formed on a substrate,optical elements such as lenses, grating couplers, diffraction gratings,etc. (for ferrule to optical element coupling) formed on a substrate.

According to the optical ferrule and the socket of some embodiments,positions of optical fibers can be finely defined at intended positionsof the optical ferrule. Also, misalignment between the optical ferruleand the socket can be restraint due to fine alignment therebetween usingthe alignment structure of the optical ferrule and the correspondingalignment structure of the socket.

FIG. 1 is a schematic diagram 100 illustrating a plan view of an exampleof a wafer on which a plurality of molded structures for opticalferrules is formed. In the example shown in FIG. 1, a wafer 102 includesa plurality of molded structures 104 for forming a plurality of opticalferrules. The wafer 102 is formed of applicable materials withrelatively smaller CTE compared to plastics, such as glass and silicon.The molded structures 104 is formed of applicable resin materials withrelatively small CTE.

In some embodiments, in forming the molded structures 104 on the wafer102, a light-activated (e.g., UV) imprint lithography may be employed.In some embodiments, a light-activated imprint lithography is carriedout in accordance with the following procedure: i) manufacturing a stepand repeat (S&R) master stamp (mold); ii) manufacturing a working stamp(mold) from the S&R master stamp; iii) forming a layer of a light (e.g.,UV) curable resin on a wafer; iv) molding a light curable materialformed on a wafer using the working stamp repeatedly for each of themolded structures; v) curing the layer of light curable resin, vi)removing the working stamp from the cured layer of the light curableresin, and vii) dicing the wafer into a plurality of diced chipincluding a diced wafer and a molded structure formed thereon. Accordingto such light-activated imprint lithography, a fine molded structure foroptical ferrules can be manufactured efficiently with lower cost.Further, selecting a suitable light curable material that has a CTEmatching with a CTE of the wafer, optical ferrules robust with thermalvariation can be formed.

FIG. 2 is a schematic diagram 200 illustrating an example opticalferrule according to some embodiments. In FIG. 2, (a) illustrates a planview of the optical ferrule, (b) illustrates a cross sectional view ofthe optical ferrule taken along line A-A, and (c) illustrates across-sectional view of the optical ferrule taken along line B-B(omitting optical fiber 208 for clarity). In the example shown in FIG.2, the optical ferrule is directed for transverse coupling andthrough-wafer transmission of optical signals. The optical ferruleincludes a ferrule substrate 202, a ferrule molded structure 204, aplurality of optical fibers 208 and an index matching filler 218.

In the example optical ferrule shown in FIG. 2, the ferrule substrate202 is a base structure on which the ferrule molded structure 204 isformed. The ferrule substrate 202 may correspond to a diced wafer, andmay be the diced wafer itself or a stacked layer of the diced wafer withone or more other layers, such as an anti-reflection (AR) layer and aprism layer for deflecting optical signals coming into or exiting outfrom the optical ferrule. In some embodiments, the ferrule substrate 202may be formed primarily of a glass, silicon, or other suitable materialhaving relatively lower CTE (e.g., 1 ppm to 10 ppm) compared toplastics. Such materials are preferable in that these materials enableflat, rigid, and easily cleanable surface to be aligned with analignment structure of a socket. In some embodiments, the CTE of theferrule substrate 202 may be matched to the CTE (e.g., 1 ppm to 50 ppm)of photonic integrated circuit elements (e.g., waveguides, couplers,multiplexers, modulators, switches, amplifiers, converters, lasergenerators, etc.). The ferrule substrate 202 formed of such materials oflow CTE and/or matched CTE may be capable of sufficiently constrainingmolded optical elements (e.g., the ferrule molded structure 204 or thephotonic integrated circuit elements) from expanding. In this paper,CTEs of two materials can be said to be matched, when the difference ofthe CTEs is less than 6 ppm.

In the example optical ferrule shown in FIG. 2, the ferrule moldedstructure 204 is a structure for accommodating the optical fibers 208and aligning with a socket to which the optical ferrule is coupled. Insome embodiments, the ferrule molded structure 204 is formed of a light(e.g., UV) curable material matched to the CTE of the ferrule substrate202. In some embodiments, the ferrule molded structure 204 has a CTE(e.g., 10 ppm to 100 ppm) higher than the CTE of the ferrule substrate202. A light curable material is preferable in that curing can beperformed at low temperature, which can avoid thermal shrinkage duringthe curing and enable excellent dimensional control. The ferrule moldedstructure 204 includes a base layer formed on the ferrule substrate 202,and a plurality of grooves 206, a reflector 210, a plurality ofreflective surfaces 212 formed on the reflector 210, a plurality ofguide rails 214, and a gap 216 formed in or on the base layer. Theplurality of grooves 206 is formed on a surface of the base layer of theferrule substrate 202 and extends from a side edge thereof towards theother side edge opposite to the side edge. Depending on the specificimplementation, the cross section of the grooves 206 may have anyapplicable shapes, such as a triangle, a hemi circle, a rectangle, andso on, so as to precisely define the position of the optical fiber 208.The “groove” may be intended to include both a recess formed in theferrule molded structure 204 and a guided space formed between twoprotrusions on the plane surface of the ferrule molded structure 204 andextending substantially in parallel to each other. Hereinafter, a recessformed in the ferrule molded structure 204 is described as a groove forillustrative purposes. Each of the plurality of grooves 206 terminatesat an intermediate point between the two side edges and has an endsurface 207 at the terminating point. The end surface 207 is formed tobe in contact with an end surface of the optical fiber 208 accommodatedtherein and configured to restrict movement of the optical fiber in theextending direction of the groove 206. The number of grooves 206 is notlimited to four, and may be any applicable number (e.g., less than fouror greater than four).

The reflector 210 is formed on the base layer of the ferrule moldedstructure 204 to face the end surfaces of the optical fibers 208accommodated in the grooves 206, respectively. The plurality ofreflective surfaces 212 is configured to reflect optical signals fromthe end surfaces of the optical fibers 208 accommodated in the grooves206, respectively. In some embodiments, one or more of the plurality ofreflective surfaces 212 includes a parabolic surface configured toconverge a flux of light of an optical signal to intensify the opticalsignal at a designed position on the optical fiber 208. The number ofthe reflective surfaces 212 may correspond to the number of grooves.

In some embodiments, optical signals from an end surface of an opticalfiber 208 is reflected by a reflective surface 212 of the reflector 210and the reflected optical signals pass through the base layer of theferrule molded structure 204 and the ferrule substrate 202. The passingoptical signals may be received by applicable devices, such as a photoreceptor and so on to convert the optical signals to electric signals.In some embodiments, optical signals from the outside of the opticalferrule (e.g., light flux emitted from a light emitting diode or laser)are reflected by reflective surface 212 of the reflector 210 and thereflected optical signals are directed to an end surface of thecorresponding optical fiber 208 and transmitted through the opticalfiber 208. In a specific implementation, a part of the optical fibers208 may be used for signal transmission into the optical fibers(in-transmission), and another part of the optical fibers 208 may beused for signal transmission out of the optical fibers(out-transmission). In another specific implementation, a single opticalfiber 208 may be used for both the in-transmission and theout-transmission.

The plurality of guide rails 214 are formed on the base layer of theferrule molded structure 204 along the extending direction of thegrooves 206 adjacent to side edges of the base layer of the ferrulemolded structure 204. The guide rails 214 serves as an alignmentstructure to be aligned with corresponding alignment structure of asocket, which is discussed below with reference to FIG. 3. In someembodiments, each of the guide rails 214 includes rounded side edges tobe aligned with the corresponding alignment structure of the socketwithout conflict. In some embodiments, the guide rails 214 may have atapered cross sectional shape (shown in (c)), such that the guide rails214 can easily fit with the corresponding alignment structure of thesocket. The number of the guide rails 214 is not limited to two, and maybe one or greater than two.

The gap 216 is formed in the base layer of the ferrule molded structure204. The gap 216 is formed to reduce stress caused in the ferrule moldedstructure 204 as a result of thermal history, which tends to peel offthe ferrule molded structure 204 from the ferrule substrate 202. In someembodiments, the gap 216 separates the layer of the ferrule moldedstructure 204, that is, the gap 216 may extend to the ferrule substrate202 and a surface of the ferrule substrate 202 may be exposed in the gap216. In some embodiments, the gap 216 extends in the extending directionof the grooves 206 and separates a part of the grooves 206 and a part ofthe reflective surfaces 212 from another part of the grooves 206 andanother part of the reflective surfaces 212. Depending on a specificimplementation, the location of the gap 216 can vary, and is not limitedto the center of the ferrule substrate 202.

The index matching filler 218 is an optional layer covering end surfacesof the optical fibers 208 and the reflector 210. The index matchingfiller 218 is formed to reduce reflection loss at an interface at theend surfaces of the optical fibers 208 and a surface of the reflector210 facing the end surfaces of the optical fibers 208. The indexmatching filler 218 is formed of a material having a refractive indexmatched with that of the optical fibers 208 and/or that of the reflector210. In a specific implementation, when the index matching filler 218 isemployed, a metallic surface may be formed on the reflective surfaces212. In another specific implementation, when the index matching filler218 is not employed, an interface between the material of the reflector210 and its atmosphere may meet a condition of total reflection. Also,an AR coating may be formed on the end surfaces of the optical fibers208.

FIG. 3 is a schematic diagram 300 illustrating an example of the opticalferrule shown in FIG. 2 coupled to a socket according to someembodiments. In FIG. 3, (a) illustrates a perspective plan view of theoptical ferrule coupled to the socket, (b) illustrates a cross sectionalview of the optical ferrule coupled to the socket taken along line B-B,and (c) illustrates a cross sectional view of the optical ferrulecoupled to the socket taken along line C-C. For better illustration ofthe structures, some of the figures of FIG. 3 and the following figuresmay include elements with solid fill. In the example shown in FIG. 3,the socket includes a socket base 302 and a socket body 304. The opticalferrule coupled to the example socket, shown in FIG. 3 and the followingfigures, may be removable from the socket by sliding or moving in adirection opposite to an insertion direction of the optical ferrule.

In the example socket shown in FIG. 3, the socket base 302 is a basestructure on which the socket body 304 is attached. The socket base 302may be formed of an organic substrate or applicable materials with arelatively low CTE, such as glass, silicon, and so on. In someembodiments, a substrate on which various applicable circuit elementsare formed for optical signal processing may serve as the socket base302.

In the example socket shown in FIG. 3, the socket body 304 is a mainstructure for coupling with the optical ferrule. The socket body 304 maybe formed of applicable materials, such as metal, plastic, and resin(e.g., light curable resin). When a light curable resin is employed forthe socket body 304, the socket may be manufactured by the light imprintlithography described above. Alternatively, the socket may bemanufactured by stamping, machining, injection molding, etc. It may alsobe assembled from multiple pieces formed by various manufacturingprocesses. The socket body 304 has a ferrule slot 306, and a pluralityof guide slits 308 and a window (light transmission window) 310 formedin the ferrule slot 306. The ferrule slot 306 is a cavity having a sideopening and in which the optical ferrule can be inserted from the sideopening. The insertion direction of the optical ferrule may be parallelto the socket base 302 or angled with respect to the socket base 302.The optical ferrule may be part of a larger optical connector. In someembodiments, the socket body 304 may be formed of a light-transmissivematerial, and may not have the window 310. In some embodiments, thewindow 310 is filled with a light-transmissive material.

In the example socket shown in FIG. 3, the ferrule slot 306 is definedby a bottom portion, side portions, and a top portion of the socket body304. The guide slits 308 are formed to be aligned with the guide rails214 of the optical ferrule. In some embodiments, the guide slits 308 mayhave a wider width at the side opening of the ferrule slot 306, for easyinsertion of the optical ferrule. In some embodiments, the guide slits308 may have a sharper edge at the end portion thereof, as opposed tothe guide rails 214, to allow for a gap between the guide rails 214 andthe guide slits 308. When the guide rails 214 have the tapered crosssectional shape, the guide slits 308 may also have the tapered crosssectional shape to match the tapered cross sectional shape of the guiderails 214. The window 310 is formed in the bottom portion of the socketbody 304 to allow optical signals to pass therethrough. The window 310is positioned to align with the reflective surfaces 212 of the opticalferrule. In some embodiments, as shown in (c), the guide rails 214 mayhave a ramped surface to be aligned with a ramped surface of the topportion of the socket body 304, for easy insertion and fine alignment ofthe optical ferrule.

FIG. 4 is a schematic diagram 400 illustrating an example of a processfor coupling a socket to an optical ferrule according to someembodiments. In FIG. 4, (a) illustrates a cross sectional view of anopen state of the socket in which the optical ferrule inserted, and (b)illustrates a cross sectional view of an engaged state of the socketcoupled to the optical ferrule. A socket includes a socket body 402 anda handle 404 formed on the socket body 402. The handle 404 is formed toallow a user to open a ferrule slot of the socket body 402 and insert anoptical ferrule while the socket (the ferrule slot) is in an open state.Once the optical ferrule is inserted into the ferrule slot and placed atan alignment position (e.g., a position stopped by the inner wall of theferrule slot), the handle 404 may be released to cause the ferrule slotreturn to an original state at which the optical ferrule is engaged withthe socket. In some embodiments, a top portion of the socket body 402,or at least part thereof, is formed of an elastic material that enablesmovement of the top portion up and down. In some embodiments, guiderails of the optical ferrule may not be ramped as in the one shown inFIG. 3.

FIG. 5 is a schematic diagram 500 illustrating another example of anoptical ferrule according to some embodiments. In FIG. 5, (a)illustrates a plan view of the optical ferrule, (b) illustrates a crosssectional view of the optical ferrule taken along line A-A, and (c)illustrates a cross sectional view of the optical ferrule taken alongline B-B. In the example shown in FIG. 5, the optical ferrule isdirected for vertical coupling and non-through-wafer transmission ofoptical signals. The optical ferrule includes a ferrule substrate 502, aferrule molded structure 504, a plurality of optical fibers 508 and anindex matching filler 518. Also, an AR coating may be formed on thelight passing surface of the index matching filler 518. The ferrulemolded structure 504 includes a plurality of grooves 506, a reflector510 including a plurality of reflective surfaces 512, a plurality ofguide pillars 514, and a gap 516. Most elements of the example opticalferrule depicted in FIG. 5 are substantially the same or similar to thecorresponding elements of the example optical ferrule depicted in FIG.2. Hereinafter, elements different from those of the example opticalferrule depicted in FIG. 2 are primarily described, and description ofcommon features will be omitted.

In the example optical ferrule shown in FIG. 5, the plurality ofreflective surfaces 512 of the reflector 510 are formed to reflectoptical signals from end surfaces of the optical fibers 508 to adirection apart from the ferrule substrate 502. That is, the opticalsignals reflected by the reflective surfaces 512 do not pass through theferrule substrate 502.

In the example optical ferrule shown in FIG. 5, the plurality of guidepillars 514 are formed on a base layer of the ferrule molded structure504 adjacent to ends of the grooves 506 and extend away from the ferrulesubstrate 502. The guide pillars 514 are formed to be aligned withcorresponding alignment structure of a socket, which is discussed belowwith reference to FIG. 6. In some embodiments, each of the guide pillars514 includes rounded side edges to be aligned with the correspondingalignment structure of the socket without conflict. In some embodiments,the guide pillars 514 may have a tapered cross sectional shape (shown inFIG. 6 (b) and (c)), such that the guide pillars 514 can easily fit withthe corresponding alignment structure of the socket. The number of theguide pillars 514 is not limited to two, and may be one or greater thantwo.

FIG. 6 is a schematic diagram 600 illustrating an example of the opticalferrule shown in FIG. 5 coupled to a socket according to someembodiments. In FIG. 6, (a) illustrates a perspective plan view of theoptical ferrule coupled to the socket, (b) illustrates a cross sectionalview of a non-engaged state of the optical ferrule placed on the sockettaken along line C-C, and (c) illustrates a cross sectional view of anengaged state of the optical ferrule coupled to the socket taken alongline C-C. In the example shown in FIG. 6, the socket includes a socketbase 602, a socket body 604, a plurality of guide holes 606, a socketlid 608, and an elastic layer 610. Most elements of the example socketdepicted in FIG. 6 are substantially the same or similar to thecorresponding elements of the example socket depicted in FIG. 3.Hereinafter, elements different from those of the example socketdepicted in FIG. 3 are primarily described, and description of commonfeatures will be omitted.

In the example socket shown in FIG. 6, the ferrule slot of the socketbody 604 is a cavity having a top opening and in which the opticalferrule can be placed from the top opening. The ferrule slot of thesocket body 604 is defined by a bottom portion and side portions. Theguide holes 606 are formed to be aligned with the guide pillars 514 ofthe optical ferrule. In some embodiments, the guide holes 606 may have atapered edge for easy placement of the optical ferrule in the ferruleslot and have a depth deeper than a length of the guide pillars 514. Insome embodiments, the socket body 604 has a surface to be aligned with abottom surface of the ferrule substrate 502 for fine alignment. In someembodiments, each of the bottom part of the socket body 604 and thesocket base 602 has a window (not shown in FIG. 6) to allow opticalsignals to pass through.

In the example socket shown in FIG. 6, the socket lid 608 is an elementto close the ferrule slot of the socket body 604 after the opticalferrule placed into the ferrule slot. In some embodiment, the socket lid608 has a surface formed to be aligned with a surface (e.g., topsurface) of the socket body 604.

In the example socket shown in FIG. 6, the elastic layer 610 is anelement to apply a down force to the optical ferrule placed in theferrule slot, for stability of the optical ferrule, after the socket lid608 close the ferrule slot. In some embodiments, the elastic layer 610may be formed of a rubber material, a spring structure, or combinationthereof. The elastic layer 610 may or may not be attached to the bottomsurface of the socket lid 608.

FIG. 7 is a schematic diagram 700 illustrating still another example ofan optical ferrule according to some embodiments. In FIG. 7, (a)illustrates a plan view of the optical ferrule, (b) illustrates a crosssectional view of the optical ferrule taken along line A-A, and (c)illustrates a cross sectional view of the optical ferrule taken alongline B-B. In the example shown in FIG. 7, the optical ferrule isdirected for vertical coupling and through-wafer transmission of opticalsignals. The optical ferrule includes a ferrule substrate 702, a ferrulemolded structure 704, a plurality of optical fibers 708 and an indexmatching filler 718. The ferrule molded structure 704 includes aplurality of grooves 706, a reflector 710 including a plurality ofreflective surfaces 712, a plurality of alignment recesses 714, and agap 716. Most elements of the example optical ferrule depicted in FIG. 7are substantially the same or similar to the corresponding elements ofthe example optical ferrule depicted in FIG. 2 and/or FIG. 5.Hereinafter, elements different from those of the example opticalferrule depicted in FIG. 2 and/or FIG. 5 are primarily described, anddescription of common features will be omitted.

In the example optical ferrule shown in FIG. 7, the plurality ofalignment recesses 714 are formed on side edges of a base layer of theferrule molded structure 704 in line with the reflector 710. Thealignment recesses 714 are formed to be aligned with correspondingalignment structure of a socket, which is discussed below with referenceto FIG. 8. In some embodiments, each of the alignment recesses 714includes a rounded surface to be aligned with the corresponding roundedsurface of the socket without conflict. The number of the alignmentrecesses 714 is not limited to two, and may be one or greater than two.

FIG. 8 is a schematic diagram 800 illustrating an example of the opticalferrule shown in FIG. 7 coupled to a socket according to someembodiments. In FIG. 8, (a) illustrates a perspective plan view of theoptical ferrule coupled to the socket, (b) illustrates a cross sectionalview of a non-engaged state of the optical ferrule placed on the sockettaken along line C-C, and (c) illustrates a cross sectional view of anengaged state of the optical ferrule coupled to the socket taken alongline C-C. In the example shown in FIG. 8, the socket includes a socketbase 802, a socket body 804, a plurality of engagement sliders 806, asocket cover 808, and a window 810. Most elements of the example socketdepicted in FIG. 8 are substantially the same or similar to thecorresponding elements of the example socket depicted in FIG. 3 and/orFIG. 6. Hereinafter, elements different from those of the example socketdepicted in FIG. 3 and/or FIG. 6 are primarily described, anddescription of common features will be omitted.

In the example socket shown in FIG. 8, the ferrule slot of the socketbody 804 is a cavity having a side opening and in which the opticalferrule can be placed from the side opening. The ferrule slot of thesocket body 804 is defined by a bottom portion and side portions. Thesocket body 804 includes a plurality of side openings in which theengagement sliders 806 can be placed, respectively. In some embodiments,a bottom portion of the socket body 804 has a surface to be aligned witha bottom surface of the ferrule substrate 702 for fine alignment.

In the example socket shown in FIG. 8, the engagement sliders 806 areaccommodated in the side openings of the socket body 804 and slidable intransverse directions. In some embodiments, the engagement sliders 806may be urged to outside direction by an elastic member such as a spring,such that the ferrule slot of the socket body 804 has a sufficientopening to insert the optical ferrule when the engagement sliders 806are not pushed by end latches of the socket cover 808. At least one ofthe engagement sliders 806 includes a tapered (or a rounded) edge at aninner bottom side thereof. The engagement slider 806 rides onto a topsurface of the ferrule substrate 702 when pushed by the end latch of thesocket cover 808 and apply a down force to the ferrule substrate 702 forstability of the optical ferrule. Similarly, at least one of theengagement sliders 806 includes a tapered (or a rounded) edge at anouter top side thereof, which enables smooth sliding of the engagementsliders 806 in the side openings of the socket body 804. The number ofthe engagement sliders 806 is not limited to two, and may be one orgreater than two.

In the example socket shown in FIG. 8, the socket cover 808 isengageable with the socket body 804. The socket cover 808 can shieldambient light from entering into the ferrule slot of the socket body804, which may cause interference of optical signals. The socket cover808 includes the side latches configured to push the engagement sliders806 inward when engaged with the socket body 804. The socket cover 808,at least part thereof, is formed of an elastic material such that theside latches expand when attached to the socket body 804 and return topush the engagement sliders 806.

FIG. 9 is a schematic diagram 900 illustrating still another example ofan optical ferrule according to some embodiments. In FIG. 9, (a)illustrates a plan view of the optical ferrule, (b) illustrates a crosssectional view of the optical ferrule taken along line A-A, and (c)illustrates a cross sectional view of the optical ferrule taken alongline B-B. In the example shown in FIG. 9, the optical ferrule isdirected for vertical coupling and non-through-wafer transmission ofoptical signals. The optical ferrule includes a ferrule substrate 902, aferrule molded structure 904, a plurality of optical fibers 908 and anindex matching filler 918. The ferrule molded structure 904 includes aplurality of grooves 906, a reflector 910 including a plurality ofreflective surfaces 912, a plurality of alignment recesses 914, and agap 916. Most elements of the example optical ferrule depicted in FIG. 9are substantially the same or similar to the corresponding elements ofthe example optical ferrule depicted in FIG. 5 and/or FIG. 7.Hereinafter, elements different from those of the example opticalferrule depicted in FIG. 5 and/or FIG. 7 are primarily described, anddescription of common features will be omitted.

In the example optical ferrule shown in FIG. 9, the plurality ofalignment recesses 714 are formed on side edges of a base layer of theferrule molded structure 904 in line with the reflector 910. Thealignment recesses 914 are formed to be aligned with correspondingalignment structure of a socket, which is discussed below with referenceto FIG. 10. In some embodiments, one or more of the alignment recesses914 includes a rounded surface to be aligned with the correspondingrounded surface of the socket without conflict. In some embodiments, oneor more of the alignment recesses 914 includes a tapered or rounded edgefor easy placement of the optical ferrule on to a ferrule slot of thesocket. The number of the alignment recesses 914 is not limited to two,and may be one or greater than two.

FIG. 10 is a schematic diagram 1000 illustrating an example of theoptical ferrule shown in FIG. 9 coupled to a socket according to someembodiments. In FIG. 10, (a) illustrates a perspective plan view of theoptical ferrule coupled to the socket, (b) illustrates a cross sectionalview of a non-engaged state of the optical ferrule placed on the sockettaken along line C-C, and (c) illustrates a cross sectional view of anengaged state of the optical ferrule coupled to the socket taken alongline C-C. In the example shown in FIG. 10, the socket includes a socketbase 1002, a socket body 1004, a plurality of engagement sliders 1006, asocket cover 1008, an elastic layer 1010, a window 1012, a plurality ofengagement latches 1014, a plurality of latch receptor recesses 1016,and an engagement edge 1018. Most elements of the example socketdepicted in FIG. 10 are substantially the same or similar to thecorresponding elements of the example socket depicted in FIG. 6 and/orFIG. 8. Hereinafter, elements different from those of the example socketdepicted in FIG. 6 and/or FIG. 8 are primarily described, anddescription of common features will be omitted.

In the example socket shown in FIG. 10, the socket body 1004 includesthe latch receptor recesses 1016 to be engaged with the engagementlatches 1014 of the socket cover 1008. Different from the end latches ofthe socket cover 808 in FIG. 8, the engagement latches 1014 may notdirectly function to align the optical ferrule with the socket, andrather function to be engaged with the socket body 1004. The socket body1004 also includes the engagement edge 1018 for fine alignment with sidesurfaces of the alignment recesses 914 and also for fine alignment witha bottom surface of the ferrule substrate 902.

FIG. 11-14 are schematic diagrams illustrating other examples of anoptical ferrule according to some embodiments. FIG. 11 is a schematicdiagram 1100 illustrating a side view of an example of an opticalferrule having a step structure according to some embodiments. Theoptical ferrule includes a ferrule substrate 1102, a ferrule moldedstructure 1104, a plurality of reflectors 1106, and a plurality ofoptical fibers 1108. In the example optical ferrule shown in FIG. 11,the ferrule molded structure 1104 includes a step structure having aplurality of steps, and each of the steps includes one or more groovesfor accommodating one or more of the optical fibers 1108. The pluralityof reflectors 1106 are disposed on the plurality of steps, respectively,to reflect optical signals from or to the one or more correspondingoptical fibers 1108.

FIG. 12 is a schematic diagram 1200 illustrating a top plan view of anexample of an optical ferrule according to some embodiments. The opticalferrule includes a ferrule substrate 1202 and a ferrule molded structure1204. The ferrule substrate 1202 includes a plurality of alignmentrecesses 1206 used for alignment of the optical ferrule with a socket.In some embodiments, the alignment recesses 1206 may be used for coarsealignment of an alignment structure of a socket (e.g., the engagementedge 1018 in FIG. 10) before an alignment structure of the ferrulemolded structure 1104 is finely aligned with the alignment structure ofthe socket.

FIG. 13 is a schematic diagram 1300 illustrating a top plan view of anexample of an optical ferrule according to some embodiments. The opticalferrule includes a ferrule substrate 1302, a ferrule molded structure1304 having a plurality of grooves 1306 and side edges 1310 foralignment to a corresponding socket, and a plurality of optical fibers1308. In the example optical ferrule shown in FIG. 13, a width of theferrule molded structure 1304 in a direction crossing an extendingdirection of the grooves 1306 decreases from a side from which theplurality of optical fibers extend out of the optical ferrule to a sideopposite to the side, and the alignment structure of the moldedstructure includes one or more side edges 1310. According to the ferrulemolded structure 1304 having the side edges 1310, no separate alignmentstructure for aligning with the socket may be required.

FIG. 14 is a schematic diagram 1400 illustrating a side view of anexample of an optical ferrule according to some embodiments. The opticalferrule includes a ferrule substrate 1402, a ferrule molded structure1404, one or more optical fibers 1408, and a prism 1410. In the exampleoptical ferrule shown in FIG. 14, the prism 1410 is disposed on asurface of the ferrule substrate 1402 opposite to a surface of theferrule substrate 1402 on which the ferrule molded structure 1404 isformed. The prism 1410 is configured to deflect the optical signalspassing through the ferrule substrate 1402. In some embodiments, insteadof or in addition to the prism 140, other functional layers may beformed on the surface opposite to the surface on which the ferrulemolded structure 1404 is formed.

It should be emphasized that many variations and modifications may bemade to the above-described embodiments, the elements of which are to beunderstood as being among other acceptable examples. All suchmodifications and variations are intended to be included herein withinthe scope of this disclosure. The foregoing description details certainembodiments of the invention. It will be appreciated, however, that nomatter how detailed the foregoing appears in text, the invention can bepracticed in many ways. As is also stated above, the use of particularterminology when describing certain features or aspects of the inventionshould not be taken to imply that the terminology is being re-definedherein to be restricted to including any specific characteristics of thefeatures or aspects of the invention with which that terminology isassociated. The scope of the invention should therefore be construed inaccordance with the appended claims and any equivalents thereof. Forexample, an optical ferrule may have guide rails and have reflectivesurfaces to direct reflected optical signals away from a ferrulesubstrate (non-through-wafer signal transmission).

Conditional language, such as, among others, “can,” “could,” “might,” or“may,” unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or steps. Thus, such conditional language is notgenerally intended to imply that features, elements and/or steps are inany way required for one or more embodiments. Alternatively, one or moreembodiments necessarily include logic for deciding, with or without userinput or prompting, whether these features, elements and/or steps areincluded or are to be performed in any particular embodiment.

What is claimed is:
 1. An optical connector comprising: an opticalferrule comprising a substrate formed of a diced wafer, a moldedstructure formed on the substrate, and a plurality of optical fibersdisposed on the substrate, wherein the molded structure comprises; aplurality of grooves for positioning a plurality of optical fiberstherealong, respectively; and a plurality of reflective surfaces formedto reflect optical signals from ends of the plurality of optical fibers,respectively, or reflect incident optical signals towards the ends ofthe plurality of optical fibers, respectively; a socket for couplingwith the optical ferrule, the socket comprising: a base; a socket bodyformed on the base, and including an opening configured to receive theoptical ferrule; and an alignment structure to be aligned to acorresponding alignment structure of the optical ferrule.
 2. The opticalconnector of claim 1, wherein the socket body includes a lighttransmission window on a bottom part of the socket body facing the base,such that optical signals from the optical ferrule pass through thelight transmission window.
 3. The optical connectors of claim 1, whereinthe opening includes a side opening from which the optical ferrule isinserted, and the alignment structure includes one or more guides alongwhich one or more corresponding guides of the optical ferrule are slid.4. The optical connector of claim 3, wherein an upper part of the socketbody defines an upper wall of the ferrule slot, and a handle is formedon the upper part of the socket body, such that the upper part of thesocket body is pulled up and the optical ferrule is inserted into theferrule slot while the upper part of the socket body is being pulled up.5. The optical connector of claim 1, wherein the ferrule slot includes atop opening from which the optical ferrule is inserted, and thealignment structure includes one or more holes that are formed on abottom part of the socket body facing the base and in which one or morealignment pillars of the optical ferrule are fit.
 6. The opticalconnector of claim 1, wherein the ferrule slot includes a top openingfrom which the optical ferrule is inserted, and the alignment structureincludes one or more engagement mechanisms to be engaged with one ormore side edges of the molded structure of the optical ferrule, the oneor more engagement mechanisms being movable along a surface of the baseand engaged with the one or more side edges of the molded structure ofthe optical ferrule by being moved by a cover of the socket.
 7. Theoptical connector of claim 1, wherein the ferrule slot includes a topopening from which the optical ferrule is inserted, and the alignmentstructure includes one or more engagement mechanisms to be engaged withone or more side edges of the molded structure of the optical ferrule,the one or more engagement mechanisms being integrally formed with thesocket body.